The invention involves a vehicle seat which has a carrier part connected to a seat back, preferably with an integrated headrest, and a seat part having a sitting surface. Vehicle seats of this type are already known in the most diverse forms. For some of these previously known vehicle seats the seat back as well as the seat part can be adjusted, so that the user of this vehicle seat can individually set and adapt the sitting position to be as comfortable as possible, particularly for long drives.
Vehicle seats of this type are, for example, also built into subcompacts which are enjoying increasing popularity. Particularly since subcompacts of this type have a comparably short crumple zone in frontal or rear collisions, extensive safety concepts are being developed for lightweight vehicles of this type, which offer the vehicle passengers as large a degree of safety as possible in case of an accident, and should be effective against serious personal injuries.
In the context of these extensive safety concepts, the vehicle seat also has a decisive significance. In general, vehicle seats having headrests are recommended which should support the user in the cervical vertebra area during a rear collision. A headrest has already been developed, which is catapulted to the front in the direction of the head during a rear collision, in order to catch the head at an early point in time.
From this an object arises, in particular, of creating a vehicle seat of the type described at the outset, which not only offers the user the highest possible degree of comfort, but also the largest possible degree of safety in crash situations.
According to one aspect of the invention, the seat back is connected to a carrier part in such a manner that the seat back is movable during a rear collision by a crash-related introduction of force through a user of the vehicle seat from a predetermined starting position to a safety position, and the carrier part has a support for the seat back, which support is arranged above the sitting surface of the seat part and is spaced by an effective lever arm from a position for introduction of forces by a pelvis area of the user against the seat back during the rear collision.
By means of this aspect of the invention, it is achieved that for a rear collision, the suspension of the back shell or the seat back, arranged relatively high above and set off at a distance by an effective lever arm from the crash-related position for the introduction of forces by the pelvis, chest, neck, and head area, brings about a generally improved moment distribution, and associated with that, a sequentially more favorable movement progression of the seat back.
According to another aspect of the invention, the seat part is connected to the carrier part in such a manner that the seat part is movable during a frontal collision by a crash-related introduction of force through the user of the vehicle seat from a predetermined starting position to a safety position, and the seat part is connected to a guide oriented on a slant upwardly and forwardly away from the seat back.
During a frontal collision, an acceleration force directed towards the front acts on the body of the user and also exercises a moment of force directed to the front on the seat part via the pelvis of the user. With this second aspect of the invention, this moment of force moves the seat part forwardly and upwardly in its restrictive guide and a retaining device between the seat and carrier part correspondingly yields. By this movement of the seat part from the originally selected starting position to the relatively higher safety position and the consequently changed sitting position of the user, the stresses on the pelvis are reduced and a submerging of the user under the seatbelt, the so-called submarining, is prevented.
It is especially advantageous if the seat back and the seat part are preferably hinged to each other at their ends which face each other, if the carrier part has connection positions for the seat back and the seat part, which are constructed in particular respectively by sliding or restrictive guides in which the seat back and the seat part are movably conducted and can be fixed in different adjustment positions using a retaining device, and if the retaining device which is effective between the seat and the carrier part for a fixed sitting position is especially yielding in an energy-absorbent manner for the movement of the seat from a predetermined starting position to a safety position during a crash-related introduction of forces.
The seat back and the seat part are thus each guided in the restrictive guides of the carrier part, which function as a seat carrier. While the joint area provided between the seat part and the seat back is arranged to be free floating, the seat back and the connected seat part can be brought by the user in their restrictive guides into an individually preferred adjustment position and fixed therein preferably in a continuous manner.
In this process, the selected adjustment position is fixed by setting the retaining device between the seat, consisting essentially of a seat back and seat part on the one hand, and the carrier part on the other hand. The vehicle seat according to the invention thus can be set in a comfortable sitting position individually within a wide range of its restrictive guides.
During a rear or frontal collision of the vehicle, a force acts on the seat via the body weight of the user, which leads to the seat back and/or the seat part moving in the restrictive guides from the individually selected starting position to a safety position. So that the seat can carry out this limited movement in a crash situation, the retaining device between the seat and the carrier part is constructed to be yielding and energy-absorbent to a certain defined extent. In this process, the retaining device can, for example, have a linkage acting between the seat and the carrier part, in which targeted bending positions or the like are provided. Thus, the seat according to the invention is distinguished by the greatest degree of seating comfort and the highest degree of safety possible.
In order to be able to transfer the pelvis movement to the seat back and to be able to parry the whiplash movement of the head during a rear collision, it is advantageous if the area of the seat back which faces the user, between its restrictive guide and its lower end area, and/or in the area of the headrest, is constructed with a comparatively low flexibility. In contrast, a preferred embodiment form according to the invention provides that the upholstery of the seat back approximately in the chest area of the user is constructed soft in comparison to the pelvis area.
A soft upholstering in the chest area provides that the support of back, neck, and head is effected simultaneously to a large extent. In particular, a zone upholstering with three zones is created, namely a 1st zone: pelvis with hard upholstery; a 2nd zone: thoracic vertebra with soft upholstery; and a 3rd zone: head with hard upholstery. In case of a rear collision, this upholstery design supports the sequentially correct introduction of forces into the shell of the seat back, and as already mentioned, provides for as simultaneous a support of the spine as possible, in particular in the upper area. Moreover, a forward-tending movement or at least a stationary behavior of the headrest is caused at the beginning.
It is advantageous if the arrangement of the seat back-restrictive guide on the carrier part and/or the upholstering of the seat back and/or the rigidity of the seat back are respectively dimensioned for an initial behavior of the seat back at least with position retention of the headrest in a catching position for the head, preferably for a forward movement, as well as for a subsequent back movement into a support position. The seat back-restrictive guide should thus be arranged at a distance above the linkage axis provided between the seat back and the seat part, preferably above the pelvis of the seat user, so that the fallback movement of the pelvis during a rear collision opposes the subsequent return movement of the head, at least in the sense of a position retention of the headrest. It is especially advantageous, however, if the arrangement of the seat back-retention guide is selected such that the return movement of the pelvis is converted into a forward movement of the headrest, which supports the head of the user at an early time, and if this forward movement subsequently follows a return movement of the seat back, such that the stresses are reduced on the neck and the head.
This movement progression of the seat back from its starting position to a safety position is supported by the above-described upholstering of the seat back, which has a comparatively low degree of flexibility in the pelvis and head area of the user and, in contrast to that, should be softer in the chest area. For the desired initial behavior of the seat back, it must be constructed to be sufficiently rigid and load-bearing.
An optimization of the ergonomics, on the one hand, and the crash behavior for rear collisions, on the other hand, is favored if the restrictive guide of the seat back runs approximately in a straight line in the longitudinal direction of the seat back.
In order also to be able to raise the front edge of the sitting surface sufficiently steeply over a comparatively short movement distance in the restrictive guide, it is advantageous if the restrictive guide of the seat part runs on a curve with a radius of curvature approximately conforming to the hip joint of the user.
In order to give the seat back as well as the seat part a sufficient stability, it is advantageous if the seat back and the seat part have a back shell and a seating shell, respectively, and if the headrest is preferably an integral component of the back shell.
A preferred embodiment according to the invention provides that the seat back and the seat part are pivotably connected together at their ends which face each other, that the seat back and the seat part are held in their restrictive guides on the carrier part at a distance from their mutual free floating pivot axis, and that the restrictive guide of the seat back and/or the seat part are constructed as rotating sliding guides.
Additional embodiments of the invention are described below and in the dependent claims.